The serum prolactin level in testicular tumours--a new tumour marker?

Serum prolactin levels were elevated above the range seen in normal male subjects of 7 of 11 patients with non-seminomatous testicular tumours, particularly in patients with metastatic disease. In contrast, the mean prolactin level in patients with seminomas was not significantly different from normal, and only one of eight patients had a serum prolactin concentration beyond the normal range. In two subjects with non-seminomatous testicular tumours serial measurements of prolactin and chorionic gonadotrophin showed a striking parallelism and accurately predicted clinical progress. Serum prolactin may be a useful additional tumour marker in patients with non-seminomatous testicular tumours.